Acre, Who was faster?
What were the results of your outing?
I’ll explain later today
– Last Updated: Feb-14-12 9:20 AM EST –
First, by using different classes of lever to move the same load, you are not providing the same force at one end of the lever as I stipulated. However, that's a problem that can be worked around to get back to the issue of what happens within the lever itself, because I can still demonstrate the the proportional relationships between the three contact forces are the same in all cases. Once that is established, it will be clear that the point I made was true when paddling, because for a given propulsive force, the force at the blade end of the paddle will be the same in all cases. After that I will show you that making the lower portion of the shaft longer increases the force that must be applied by your two hands.
In the meantime, use your horse sense to figure this out: Since ultimately you need to use the blade to apply propulsion against the water (the force of blade against water = the force that pushes the boat when you are paddling), imagine your first scenario and pull the canoe across the ground that way. Now get a paddle that's twice as long and do the same task, but with your lower hand located the same distance from the grip hand as when you used the first paddle. You told me earlier that you have more mechanical advantage in that case because the paddle is longer. Do you still agree with that statement? Which side of the lever actually has mechanical advantage in this case, your hands, or the blade?
More later.
Haven’t gone yet
We initially discussed this last fall and it never worked out. We need to coordinate the shuttle,our shared free time and the weather not to mention river conditions and family responsibilities… Since we’re in New England we may not get an ideal time to go out until later in the spring. I feel confident that I can to the ten miles on flat water without getting wet but I’m not sure about my friend especially if the conditions are less than ideal.
The recent post was perhaps initiated by a discussion that involved alcohol. I might have mentioned to him that I would have to spend a lot of time waiting for him to catch up even with the burden of carrying all his gear. Honestly I am surprised at the amount of traffic the post has received. When the trip does happen I will do my best to make the single blade crowd proud and I will report the results.
What! Another Futile Exercise?
Twice as long? Now I got to get a step ladder. I prefer to use the second scenario, which actually duplicates how a paddle actually works in the water as a lever, for the water is the fulcrum, as proven in that Quickblade video of the SUP paddle blade exiting 8 inches ahead of where it entered. Remember the eyes are deceiving, for the SUP is pivoting past the blade and this video confirms this, no matter what the math. On the other hand, maybe these elite paddlers are using the paddle as a foil?
I see it;s useless
– Last Updated: Feb-14-12 3:36 PM EST –
Actually, I'm offering to answer the questions you posed but without straying from the point in the way that you did when asking them. And now you don't want to hear it? Why am I not surprised.
Anyway, you are not understanding my words, nor my intention. For example, the purpose of showing what happens with a longer paddle is to compare the SUP paddle to the canoe paddle. Remember, that's what this was all about. Making the paddle twice as long is a way of making the comparison between a long paddle and short paddle easier than if it were, say, 1.3-times as long. It would illustrate a principle, horse sense as you would say. No need to measure everything to the fraction of an inch if the purpose is merely to illustrate a trend.
I bet you don't understand.
Not sure when I'll have time to TRY to show you what I've been saying yet today. Trust me, you are not understanding me at any step along the way. Or DON'T trust me about that. It's not that I care. I just thought it might be fun to illustrate some basic lever principles and conclusively show that greater force needs to be applied to the top grip and shaft of the paddle if the part sticking down below your lower hand is a lot longer. None of your responses address actual points I've stated. Maybe numbers will make it clear, but we'll see.
Simply Tell Me The Work To Be Performed?
Then maybe I’ll get it? For there are only three (3) components that make up a lever: load, fulcrum, and force. If the load is in the middle, then it is a 2nd class lever. If the load is at the ends, then it is either a 1st or 3rd class lever. What can be any simpler than that? So with the SUP, I’m assuming the fulcrum is the water, the force is the top hand, and the load or SUP is in between the fulcrum and the force. So with the longer paddle, I might just vault right off the board?
SUP vs. Surf Ski
Check out this Rambo video of the “Doctor” race recently held in Australia, where SUPs, although given an hour head start, nearly finished ahead of the surfskis.
http://vimeo.com/35749053
You can bet the SUPs won’t be given as generous a headstart next time?
Improvement
This might already have been done, but it seems to me if you took a SUP, put a skeg on it, then a centreboard, and finally a mast/boom/sail, you’d have a very fast craft for that sort of race.
Actually, Just The Opposite Was Done
When sailboards or windsurfers were stripped to make them SUPs in the modern early beginnings of this sport before dedicated SUPs came about.
Way-back machine…
– Last Updated: Feb-15-12 11:50 AM EST –
http://en.wikipedia.org/wiki/Sailfish_(sailboat)
Cut&paste that whole line on your browser.
Hawai’i
I could be wrong, but I thought the natives of Hawai’i were paddleboarding for several dozen generations.
Not the reason.
– Last Updated: Feb-14-12 11:53 PM EST –
I was hoping that once the forces are quantified, I'd be able to convey to you the few points that I've been trying to make but which have been flying right by you all this time. That's all. Clearly there's a communication problem going on, because all this talk of classes of levers is irrelevant and unnecessary, but that SHOULD finally become apparent. I had no free time today though, so I didn't do it.
Yes They Were
Paddling stand up many years ago. And I should of said revival of the sport, which really took off as a brand new world wide industry within the last 8 years or so.
I’m Sorry Guideaboatguy
But your three forces or triple force lever completely stumped me, for I never heard of such a lever? Do you mean compound levers?
No, that isn’t what I mean
I figured something must be getting lost in the translation. Each type of simple lever has three points along its length where it comes in contact with something other than itself. There’s contact with the object being moved, contact at the place where a person pushes or pulls, and contact with the fulcrum. There’s a force applied to the lever at each of these locations, as I described in earlier posts. Your responses to what I’ve said about certain forces sometimes indicates a working definition that is different than what it means in physics, and therein lies part of the misunderstanding, I think. If you were a lot more ambitious than most people (myself included) you could look up some articles on “statics”, which is the study of forces that are in balance, if you were interested, but but it’s a long shat that anyone would feel like doing that, or have the time to. I guess the bottom line is that I have failed to communicate clearly, for whatever reason.
Now We’re Getting Somewhere
Thank you for clearing up the misconceptions, for indeed, we do not share the same “frame of reference.” Like when you said “push and pull,” I couldn’t understand why you wanted to balance the forces? Doing that creates equilibrium, and the canoe remains at a standstill. Is that what you were trying to explain?
Not exactly
Forces which propel a moving object can be balanced too. “Statics” means that at the moment being analyzed, the forces are not changing, but the object undergoing the forces is often moving. One everyday example is the driving force that moves your car. At any given speed of travel, the driving force occuring where the tires meet the road is conterbalanced by friction within all the moving parts plus wind resistance. A strong driving force is needed to keep a car moving at highway speed. It is simple to imagine the driving force to push a car against a stationary brick wall, but pushing against air resistance at high speed creates a situation which can be analyzed the same way.
While the canoe paddle is providing a propulsive force, the canoe is being driven forward and even though we like to think of “planting the paddle” and “pulling the boat past the blade”, the blade is actually slipping backward through the water a very small amount, but in spite of both the boat and paddle being in motion, all forces are balanced. That’s why it’s helpful to focus only on the forces experienced by the paddle itself in this situation. Once we know that the forces are balanced, we need not worry about whatever motion is occuring.
Clyde you should profile …
I get the sense that you are the only one in this conversation that has much sense of SUP / ocean paddling. You should fill in your profile so people have an idea where you are coming from.
I have to admit with a last name like Hedlund I thought you were probably a viking.
My experience was on the ocean
If anything, I think the ocean would tend to give canoe a greater advantage over a 10 mile distance because of the extra energy staying up that the SUPer would have to expend. But that’s just a hunch.
"Slipping Backwards"
Like in Newton’s 2nd Law? I guess for most of us, “slipping backwards” doesn’t make a bit of difference? But if you’re splitting hundredths or thousandths of a second, then you’ve got some serious stroke defects and you better stick with Newton’s 3rd Law. Anyway, thank you, for I thought when forces were balanced, they cancelled out, and only when they were unbalanced did propulsion occur?